Trudeau said the prime minister's assertion is an insult, not just to him but to the 18 armed forces vets who are running for the Liberals in the next election and to all Canadians who believe in freedom of speech.

Trudeau was responding to remarks Harper made Sunday in an interview with a London, Ont., radio station.

Referring to the Liberals' decision last fall to oppose Canada's participation in airstrikes against Islamic extremists in Iraq, Harper said: "I do think Mr. Trudeau's comments around the time of the debate indicate a deep distrust and, frankly, dislike of the Canadian military that I think runs very deep in some elements of that party and with him."

At that time, the Conservatives accused Trudeau of showing disrespect for the military after he quipped that Canada should be involved in providing humanitarian aid to Iraq "rather than trying to whip out our CF-18s and show them how big they are.”

In the text of a speech delivered Thursday to party faithful in Calgary, Trudeau began with a lengthy tribute to Harjit Singh Sajjan, a celebrated military vet and star Liberal candidate in Vancouver. Sajjan served in Bosnia and three tours in Afghanistan, becoming the first turbaned Sikh to command a Canadian army regiment.

"He is a genuine Canadian hero and when Stephen Harper attacks my deep personal respect for our forces, he insults not just Harj, not just the 17 other Canadian Forces veterans who have chosen to follow me as Liberal candidates in the next election," Trudeau said.

"But (he) insults every Canadian who believes that we should have the freedom to disagree with each other politically and not be called a lesser Canadian for it."

Trudeau added: "Let's honour those who have fought and died for our democracy by keeping it healthy. We can debate each other's policies but not each other's patriotism."

The speech was devoted primarily to Trudeau's contention that Harper has mismanaged the economy — a recurring theme for the Liberal leader in recent weeks as the collapse in oil prices sucks billions from the federal treasury and stifles economic growth.

Harper, who hails from Calgary, has not been a champion of Alberta, Trudeau maintained. Indeed, he argued that Harper's refusal to mollify American environmental concerns and tackle climate change has made it impossible to build the pipelines Alberta needs to get its oil sands crude to tide water.

A Liberal government would "get serious about climate change" and work with allies like the United States to ensure Alberta's resources get to market and get a fair price, he promised.

Trudeau has not spelled out his own plans for the economy but he offered a few vague hints in Thursday's speech, promising to fix the Canada Pension Plan "so that it can provide an adequate pension" and to give "tax relief to middle-class Canadians who really need it, like those who have trouble keeping up with the cost of living."